otellogr: Implement Error and comment Init (#6295)

Implements remaining methods and adds to the changelog

Part of
#5192

---------

Co-authored-by: Damien Mathieu <42@dmathieu.com>
Co-authored-by: Robert Pająk <pellared@hotmail.com>

bridges/otellogr/go.mod

@@ -5,14 +5,14 @@ go 1.22
 require (
 	github.com/go-logr/logr v1.4.2
 	github.com/stretchr/testify v1.9.0
+	go.opentelemetry.io/otel v1.32.0
 	go.opentelemetry.io/otel/log v0.8.0
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	go.opentelemetry.io/otel v1.32.0 // indirect
 	go.opentelemetry.io/otel/metric v1.32.0 // indirect
 	go.opentelemetry.io/otel/trace v1.32.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

bridges/otellogr/logsink.go

@@ -13,6 +13,8 @@
 //   - Level is transformed and set as the Severity. The SeverityText is not
 //     set.
 //   - KeyAndValues are transformed and set as Attributes.
+//   - Error is always logged as an additional attribute with the key
+//     "exception.message" and with the severity [log.SeverityError].
 //   - The [context.Context] value in KeyAndValues is propagated to OpenTelemetry
 //     log record. All non-nested [context.Context] values are ignored and not
 //     added as attributes. If there are multiple [context.Context] the last one
@@ -59,6 +61,7 @@ import (
 
 	"go.opentelemetry.io/otel/log"
 	"go.opentelemetry.io/otel/log/global"
+	semconv "go.opentelemetry.io/otel/semconv/v1.27.0"
 )
 
 type config struct {
@@ -206,7 +209,20 @@ func (l *LogSink) Enabled(level int) bool {
 
 // Error logs an error, with the given message and key/value pairs.
 func (l *LogSink) Error(err error, msg string, keysAndValues ...any) {
-	// TODO
+	var record log.Record
+	record.SetBody(log.StringValue(msg))
+	record.SetSeverity(log.SeverityError)
+
+	record.AddAttributes(
+		log.String(string(semconv.ExceptionMessageKey), err.Error()),
+	)
+
+	record.AddAttributes(l.attr...)
+
+	ctx, attr := convertKVs(l.ctx, keysAndValues...)
+	record.AddAttributes(attr...)
+
+	l.logger.Emit(ctx, record)
 }
 
 // Info logs a non-error message with the given key/value pairs.
@@ -223,9 +239,12 @@ func (l *LogSink) Info(level int, msg string, keysAndValues ...any) {
 	l.logger.Emit(ctx, record)
 }
 
-// Init initializes the LogSink.
+// Init receives optional information about the logr library this
+// implementation does not use it.
 func (l *LogSink) Init(info logr.RuntimeInfo) {
-	// TODO
+	// We don't need to do anything here.
+	// CallDepth is used to calculate the caller's PC.
+	// PC is dropped as part of the conversion to the OpenTelemetry log.Record.
 }
 
 // WithName returns a new LogSink with the specified name appended.

bridges/otellogr/logsink_test.go

@@ -4,6 +4,7 @@ package otellogr
 
 import (
 	"context"
+	"errors"
 	"testing"
 	"time"
 
@@ -277,6 +278,49 @@ func TestLogSink(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "error",
+			f: func(l *logr.Logger) {
+				l.Error(errors.New("test"), "error message")
+			},
+			wantRecords: map[string][]log.Record{
+				name: {
+					buildRecord(log.StringValue("error message"), time.Time{}, log.SeverityError, []log.KeyValue{
+						{Key: "exception.message", Value: log.StringValue("test")},
+					}),
+				},
+			},
+		},
+		{
+			name: "error_multi_attrs",
+			f: func(l *logr.Logger) {
+				l.Error(errors.New("test error"), "msg",
+					"struct", struct{ data int64 }{data: 1},
+					"bool", true,
+					"duration", time.Minute,
+					"float64", 3.14159,
+					"int64", -2,
+					"string", "str",
+					"time", time.Unix(1000, 1000),
+					"uint64", uint64(3),
+				)
+			},
+			wantRecords: map[string][]log.Record{
+				name: {
+					buildRecord(log.StringValue("msg"), time.Time{}, log.SeverityError, []log.KeyValue{
+						{Key: "exception.message", Value: log.StringValue("test error")},
+						log.String("struct", "{data:1}"),
+						log.Bool("bool", true),
+						log.Int64("duration", 60_000_000_000),
+						log.Float64("float64", 3.14159),
+						log.Int64("int64", -2),
+						log.String("string", "str"),
+						log.Int64("time", time.Unix(1000, 1000).UnixNano()),
+						log.Int64("uint64", 3),
+					}),
+				},
+			},
+		},
 	} {
 		t.Run(tt.name, func(t *testing.T) {
 			rec := logtest.NewRecorder()